Conventionally, coating films having high lightness have been formed on the outermost layers of exterior parts, ornaments such as glasses, accessories, and timepieces, decorative articles, sporting goods, and the like to make the high-quality appearances thereof. For example, Non Patent Literature 1 describes that a hard coating film comprising titanium carbide is formed on a base with stainless steel, titanium, or the like by a dry plating method, to produce a case or a band for a timepiece. Scratch resistance can also be improved by forming such a hard coating film.